This bulletin released by GM applies to diagnosing multiple electrical concerns, intermittent no-crank or DTC C0900, with regard to 2007-2014 Cadillac Escalade models.
In rare cases, some customers may experience one or all of the following concerns:
1. Intermittent no-crank or no vehicle power (the customer may get the impression that the vehicle battery is dead).
2. Volt gauge fluctuates and seems to decrease when a high load accessory is turned on (headlamps, wipers, etc.).
3. IPC backlighting flickers or the IPC goes blank.
4. DTC B1325 is set in several modules followed with a DTC C0900 set in the EBCM.
5. Radio clock resets.
6. Intermittent stall (the customer would have noted a DIC indication of “battery low” or the battery lamp is illuminated).
7. HVAC temperature actuator defaults to hot.
8. Door locks cycle.
When diagnosing any of the above concerns and a cause for the concern can’t be identified, check the following items:
1. Remove the 175 amp Mega Fuse and inspect for arcing. If any type of arcing is found, replace the affected components.
2. When reinstalling the 175 amp Mega Fuse, torque fasteners that attach the mega fuse to the positive cables to the specification found in the service manual.
3. Check the voltage drop reading on the positive battery cable that runs from the battery to the underhood buss electrical center (UBEC).
4. Check the voltage drop reading on the negative battery cable that runs from the battery to the engine block. When checking voltage drops, the voltage drop should be performed with the fuel injectors disabled and while cranking the engine. MIN/MAX on the digital multimeter (DVOM) should not be used. The voltage drop should be monitored at a steady crank. The voltage drop should not exceed 200 mV. If the voltage drop is above 200 mV, replace the affected cable.
5. Check the cable that runs from the battery to the starter for proper torque, terminal connections, and for an open short circuit. Starter cable open circuit would be checked only when both ends of the starter cables are disconnected (at battery and starter) with a DVOM.